Process and apparatus for coating particulate material



1951 D. E. MARSHALL 9,

PROCESS AND APPARATUS FOR COATING PARTICULATE MATERIAL Filed April 9, 1945 2 Sl-IEETS-Sl-IEET 1 IMVENTOR [flaw/1M MA/is TTORNEY Dec. 25, 1951 o. E. MARSHALL PROCESS AND APPARATUS FOR COATING PARTICULATE MATERIAL Filed April 9, 1945 2 SHEETS-SHEET 2- INVENTOR flonald E Marsha/l ATTORNEY Patented Dec. 25,..1951

UNITED star as oer-i cs PRGEESS ANDAPARATUS FORICOATING PARTICULATEEMATERIAL Donald E. Marshall, Sumn'iiLYN 1., assignorto Colgate-Palmolive-Peet 'Company','' a corporation of Delaware implication April 9, 1945;:SerialNo.':58,7;404

16 Claims.

. This invention relates to a process andapparatus for treating materials that comprise )liquics that carry solids, suchas soap mixtures, wetting agent. mixtures, milk, fruit juices, coffee .solution, plastic solutions, starch solutions, sugar solutions, chemical solutions, and the like.

Incarrying out-the invention, liquids having -.solids-dissolr-ed or mixed therein are sprayed or -flashed-on amovi-ngbedof finely divided solid particles in such a way; that great exposure to heat, vaporization or chemical reaction occurs 1 on the surfaces of these particles. The moving :bed of particles is fluidized .byaerationand flows through a-closed system easily adaptable to gain almostanycondition of time, temperature, presl ,sure-orrecycling. requiredto carry out a drying -cycle a chemical reaction or a particle formation for the solids in the original solution.

Some of the advantages of the invention are that the equipment used has large reaction cai pacity in proportion to its size; the time required -.-toremove the solids from the, liquids can be controlled; the size and density and structure .of'the solid particles obtained from the liquids scan-be varied; .theltemperature to which-the --.ma,terialis subjected can be easily regulated; injury of-the products Icy-erosion, adhesion to surfaces, overheating 'isminimized; very little, I if any dust is produced; and the closed system in'which it operates permits the use of heat from avariety of heat sources; also differential vapor r. pressures may be developed by. heat, vacuum or conditioned aeration gas to promote a wide range of reactions.

All this can be accomplishedwi-th this. lnven-= I heat transferbetween' solids and gases and be-- 1 tween a fluidized mass and sources of heatis obtained; delicate and sticky particles can be treated until they are'sufficiently dry and cool to be handled safely for delivery to a packaging center; particlesof solids" that are smaller than desired are recycled to produce particles of the proper size, density and structure; input either as a vapor or as a liquid. spray. carryingsolids is "introduced. to effect the particle. formation that I "is desired; which may include multi-sta'gesp'ray- The invention maybe carried out with diif ervent arrangements- 0f.- apparatus, two of which ware.- illustratedin the accompanying drawings ,whichtv are somewhat, diagrammatic,illustrations -of; apparatus suitable for carrying out the inzvention.

-In the. drawings Fig.,1 is;;a-;side view may in vsecition showing an arrangement of apparatus tor carryingoutthe invention;- and i'EigJFZ isapsimilar vievv showing a modification.

.In'F'Fig. 1 fofithe. drawings, reference character i I indicates aiblower'for forcing hot. gases into =the"conduit or pipe Z whichis connected to" the f bcttompf the heater 3 of the'multi-tube type. ""Ihis heater comprises a-chamber 4 that isprovided-with a plurality of parallel tubes-5 with their ends anchoredin headers 6. An inlet 1 for-"steam anqan outlet 8for'thecool steam or water are provide xi in-';the usual way for supply- -ing heat td-the heater 3.

' A spray chamberlll which is-circular in crosssection -has a comically-shaped bottom with? a f centrarfiat portion" into which the tubes "5 enter. An{annularadjustable: baffle or filler l I' 'is lo- "cated "inthe'lo'w'er portion of'the chamber [0 and iss'paced fromthe bottom or the chamber. It

of such a-s'ize th'at an annular passage i2 is'provid'ed'i'between"itsedge andcthe inside wall of the-chamber "Hi. "This annular passage is ofan 0 areas of the ;;insides*'-of the tubes 5.

'of the baffle" l "is'corrugated, as indicated at I 3, with" the corrugations decreasing insize'or-height toward the) center. "A pipe I4 is provided with r into the insideE'Ofthe chamber{I0 for spraying area 'about-equal 'to' thejcombined cross-"sectional The inside spray nozzles *l 5 arranged on a circle; extending the'liquids-"carryingjsolids into this chamber. 'A

ifs'tea'mheater l6 isprovided for heating theliquid :that-"isintroduced, through the pipe' l4.

An outlet-.18 has its lower open end projecting Pb'elow the *fluid-ized solids surfaces I9 inithe chamber" I0. {Thisyoutl'ethas a non-metallic section 20* outside of the chamber l'0 'around which a concentrated 'electrostaticfffi'eldj iisfgenerated byghigh 'fre'quen'cy' electric current that is 3 applied along the outside thereof by electrodes 21 to which the leads 23 are connected.

A chamber 25 similar to thechamber I is provided, into the central lower end of which the outlet l8 enters. The adjustable baffle 28 in this chamber is similar to the bafiie II, the passageway 21 is of the same cross-sectional area as the tube 28, and the corrugations 28 are similar to the corrugations [3. An inlet pipe 29 with spray branches 38 and a heater 31 are provided which are similar to those described above.

The outlet 33 from chamber has its lower end extending below the fluidized solids surfaces 32. Infra-red electric lamp heaters 34 are located outside of chamber 25 around this outlet 33 for heating the products that pass therethrough. The outlet 33 enters an expansion stack 38 tangentially. This stack has an outlet 31 at the top for escape of gases. A flexible connection 38 extends from the bottom of the stack 36 to a separator or classifier 39 for particles of difierent sizes. This separator may be of the vibrating air-table type which is provided with an aerating ,device 40 to cool and aerate the particles of materials by air which enters through the inlet 40' after these particles pass through the flexible connection 38. Reference character 43, 44 indicate diagrammatically means to support and vibrate the classifier table 39. A gas or vapor outlet 45 is provided from the classifier table 39. A valved outlet 46 is provided for small size particles that are to be recirculated and built up in size by being returned to the system. These particles are introduced into the hopper 41 and thence into the pipe 48 which is connected to the conduit 2. Fine particles of the material to be treated may be introduced into hopper 41 from source A when desired. A gas inlet 41 is provided at the top of hopper 41 and a slide valve 48 is provided near the lower end of pipe 48 to induce and regulate the flow of solid particles.

A valved outlet 46' extends from the classifier table 39 for the suitable or desired sizes of material which enter the tube 50 and are then carried by the gas entering pipe 41" under pressure and the fluidizing gas or compressed air introduced by blower 50' through pipe 5| to the lower end of-the cooler 52 that is cooled by cool water entering at inlet 53 and leaving by outlet 54. A conduit 55 leads from the top of the cooler 52 and enter an expansion stack 58. Solid particles pass through the flexible connection 51 to a classifying separator 58 which is adapted to separate particles that are either too fine or too coarse from particles of desired size. A conduit 59 extends from the separator 58 so as to return gases from this separator to the outlet 88.

A valved conduit 6| is provided at the lower end of the table 58 to remove particles that are too fine or too coarse and therefore need to be re-treated or re-worked in the apparatus after the coarse particles have been broken up. A valved conduit 62 extends from the table 58 for introducing particles of the right size into the elongated container 83. These particles are carried by the gas or compressed air that is introduced at 84' and the fluidizing air introduced at 68. An outlet 65 is provided at the bottom of the container 83 with a valve 66 at its lower end. Thi outlet enters conduit 61. The conduit 61 extends to a conveying and packaging system indicated at 10 where the particles of the desired sizes are packaged for shipment. Vents 69 are provided for escape of fiuidizing air.

lnthe modification shown in Fig. 2, the vapors are removed immediately after each spraying operation to decrease the pressures that would otherwise oppose vaporization. Two solutions of different sorts of material may be treated or dried simultaneously to provide solid particles that may be non-homogeneous.

In this Fig. 2 reference characters 15 and 15' indicate conduits through which materials to be treated are introduced. These conduits correspond somewhat to the conduit 2 in Fig. l. The heaters 18 and 16' heat the materials passing through the conduits and the conduits enter the bottoms of the spray chambers 11 and 11' that are provided with spray nozzles 18 and i8, respectively. The baffles 19 and 19 in these spray chambers are provided with sloping corrugated surfaces. The outlets 88 and from these spray chambers extend below the surfaces of the fluidized material in these chambers and the outsides thereof are heated by the heaters 8| and 81'. These outlets extend into the bottoms of the vapor release chambers 82 and 82. These chambers are provided with sloping plates or tables 83 and 83, having their upper surfaces corrugated as indicated at 84 and 84'. Outlets 85 and 85 to the atmosphere are provided for the vapors released in the chambers 82 and 82'.

The pressures within the spraying chambers 11 and 11 may be kept very low by causing the outlets '80 and 88' to extend only far enough into the vapor release chambers 82 and 82' to maintain the seals.

Classifier tables 86 and 88 similar to those described in connection with Fig. 1 are provided to receive the solid materials from the chambers 82 and 82' and classify them. The plates or tables 83 and 83' may be caused to perform the same result as air-tables 86 and 86 by providing a vibrating means and inclining the plates so as to deliver particles that are classified as to density or size directly into outlets 88, B8 and 90, 98.

Theclassifier tables 86 and 86 are provided with gas outlets 81 and 81' to permit the gases to escape to the outside. Valved outlets 88 and 88' are provided at the lower edges of the classifiers 88 and 86'. These outlets are connected to valved return conduits 89 and 89 that are provided with adjustable valves 90 and 90'. A conduit 9| for the finished material is connected to valved outlets 93, 93 and to the conduit 92. Conduit 92 corresponds to the conduit 5| in Fig. 1 and delivers to cooler 94 in the same manner that conduit 51 delivers to cooler 52 in Fig. 1. The cooled finished product is handled in the way described in connection with Fig. l.

The operation with the apparatus shown in Fig. 1 is as follows:

Solid particles of the material to be treated are fed into the feed column 48 which drives the circulation of solid particles in the system. This column 48 may be provided with the upper container 41 to provide space for a supply of solid particles of the material and thus add flexibility to the system. When wall friction of the system is excessive, gas under pressure may be introduced by inlet 41 at the top of the container 41 to maintain the circulation, in which case the container 41 is provided with an air lock of the known sort.

Heated gas is introduced by blower l to the extent that is needed to fiuidize the mass of material. This gas may be the products of combustion of water gas or fuel oil for instance, so as to avoid oxidation which otherwise might be deleterious to the product that is to be subjected toffsuch" temperatures and exposuresi- Since the volume of gas needed to fiuidize the material under pressure in the system is only about-equal to the volume of the material that is being processed when this material consists of granules of soap; for example, only a small portion of the heat required to vaporize the liquid in chamber Ht needs to be introducedas hotgas through 0011-" dint-2r More heat is better supplied by the heater 3" due to the'steam that'is'introduced around the tubes 5from inlet I: The solid particles entering through conduit 2 are fluidized'an'd flow through th'ese tubes 5; The'solution of the material which isto be treated is sprayed in from pipe M after it has" been made sufficiently hot by heater it to vaporize nearly all of the liquid that enters" chamber H3, or'anydesired portion thereof.

- Theh'ot gases from blower l fiuidize the'particle'sthat enter conduit 2'from pipe 48- through the heater 3 into the bottom of chamber 19 and spill over the outer edge of baffie ll but do not entirely" fill the chamber it due to the pressure maintainedtherein. These particles are to be treated so as to obtain particles of the desired size by' adding oneor more layers of solid materialto the particles. The entering gas fluidizes theparticles in chamber lfi'so that-the mass boils and-flows'similar to a liquid.

The hot solution of the material that is sprayed into the chamber lficoat's theturbulent particles of the material. This turbulence is aided by the particles passing over the corrugations l3, and pressure in this chamber causes the fluidized and coated particles to pass upwardly through pipe I8.

Al's-the high frequency electric heating is applied to the material while it is passing through the conduitzfi" thestream'of fluidized solids is subjected to a concentrated electrostatic high frequency elec tri'c' field that is established so that the product stream itself is used as the di-eleotrie. Inthis way molecular vibrations are set up in thematerial whichwill intensely heat theparticles 'thereof, thereby driving the vapors out in a most effective manner, thus producing a type r of particle which possesse'svery desirable structure as to solubility.

These particles then pass into the chamber in" their fluidized state where they are coated again by means of the solution that is sprayed in by the Sprayers 30. The fluidized particles are then forced through the conduit 33 where they are subjected to theheat from the infra red lamps 32- which dries them. The treated prod-' ucts then pass'into the expansion stack" 36.

The vapors which are separated from the solids instack 36 pass out through the outletSl and the solid particles pass downwardly into the classifier 39. The particles that have been built up to the proper sizes and densities, but not necessarily cooled or conditioned, are separated from the recycling stream by the air table 39 and are routed into the conduit 50.

' These particles are driven into the second or conditioning system where they are aerated or fluidized and cooled. Since the cooler 52 of this conditioning system comprises a shell and tube heat exchanger and the fluidized solids pass through the tubes and cooling water is supplied around the tubes with proper turbulence, the fluidized particles are passed in the turbulent manner over the cooled surfaces of the cooler and are delivered properly conditioned to the pressure release stack 5B. 7' Th' conditioned arades ar'e'giveri a final gradingbyfl'iieahs"ofafir table" 58*whlch remo the fines and delivers" them to the' rcycli system. Oversizeparticlesfcaii also be recovered and groundor milledto finepa'rticles and also? placed in"th"e ecycling stream;

When" the finished" product'- is to be"c'Oi1Vyed to a packaging point a system similarto tlieworr ditioning portion but, without the coolercan be used to convey and distribute the product with out damage directlyxtojthe c'artonerorsimilar packagingequipment 5'3"; 1

The baffles lla'ndzfi may bemade adjustable with respect to'conduits' ltf'and 33*in the fiui izingcharnbers i ii'andfi, :thus increasing'and"d creasing" the depth of the bed that being sprayed and providing the'desired sprayingspace'" above thefluidized mass;

Since the" sprayers I 5 and 33 arelocate d"' co'n centrically' above the boiling surface of fluidized solids it desirable to? have" them adjustable vertically so as to coat the particles" properly when the surface of the bed is'changed.

Thetelhperature" of thesolutionand the tem=-=- pe'rature andcondition of the material that being treated can be ascerta'inedbytrial andcaii be held'at the requiredpoint'toobtain the desired degree of adherence of new solids to particles" previously in the heal; 4

Also, suoeessivefc-catings oi the particlescanbe obtaihed when desired. by 'applyingone sd'rt of solution such as builders" inthe" case'of" soap'f manufacture in the first chamber it followed byanother sort of solution sucii as straight soap in the second oharnber25.

. The infra red radiation from lamps esremnves' the moisture that was introduced through sprayers 30.

With this system of heating, wiue'choicesa-riej provided for gainingsimplicity, efficiency, prod uct characteristics, besides providing safety fiorn fire or explosionhazards. Superheat'edsteam may be used instead of hot gas from" blower to increase the safety when productsaretree ed that will withstand the temperatures that reached;

The sort of gaseous material thatis to beintro= duced by means" of the'blower' I" may" bedeter mined sometimes by the reduced temperatures needed' to' produce the finished" productl Fares g ample,.if. the material is'to' be treated at"a' te'rrt-- peraturjebelow room" temperature" thegas should be sufficient; in" amount and dried *sufi ib'iently tb" have" the' high va or carryin capacit that-i s needed. 7

When the material to be processed is suohthat higher temperatures areper'rnissible" the capacity of the gas to carry vapor can be easily increased? Also, vapor-as such will separate and serve as aerating'g'as; But the temperatures should not: be above the melting points of thesolids 'thatatei to be treated 'aftl" makifig allowallifie for the cooling effect of evaporation. v

This systemcan also he ernployedwhere pres"- s'ur'es below atmospheric are maintained by exhausting from the system sufiicient gas and vapor-1 to maintainfla negative pressure within. The difi'fential pressures Within the system and the hydrostatic heads necessary to cause the flovg of fluidized mass can still be obtaln'ed. Fur: thermore, the Vap oi" pressures develop d' in the" liquid surfacesmay be sufficiently high to convjeitthese liquids 156 a vapor that is swept out of the system as isj in great excess of the vapor capacity of the fluidizinggas introduced by bin er 'I; Iiisutih as'ystem" and Where aire ipeusivt inert gas is used as the aerating medium, the mixture of vapors and inert gas which are exhausted from the system may be compressed to the degree necessary to cause separation of the liquidized vapors, leaving the separated and compressed inert gas to be reused as the aeration gas in the system.

In carrying out the invention the entrainment of dust can be minimized by aerating the material that is to be processed only enough to provide turbulence needed for heat transfer or for contacting of gas with solids or for particle formation; and the damage to particles by erosions can be decreased by using large enough ducts and vessels to reduce the velocities of the gas sufficiently so that it does not entrain the solid particles to an objectionable extent.

The flow of material through the system is regulated by the difference in weight of solids plus the air pressure in the densely fluidized feed column 48 and the weight of the low density fluidized solids included in ducts and chambers between inlet 2 and outlet 33, plus whatever back pressure exists in the stack 31. This flow can be regulated by slide valve 48'.

In order to avoid caking of the solids in column 48 the compressed air may be introduced some at 41' and also some along the length of column 48 down to slide valve 48' as indicated at 49.

The original supply of the solid particles can be effected by adjusting the system until a suitable bed of material is obtained. Or the bed of material can be produced in a separate conventional spray drying chamber or other suitable device.

The solids bearing feed solution is introduced through pipe l4 into the fluidized chamber Ill according to conditions which will carry away the desired amount of vapor.

The solution introduced through inlet 29 may be superheated to flash at the spray exits 30, thus forming very fine solid particles of which the sizes are determined by the nozzles on sprayers 30 and the pressure that is applied. This particle size may be small and therefore the optimum for vapor release regardless of the size of the final particles desired. These particles will grow as they are recycled and as layers of solid are added from the solution that is introduced by vaporizing nozzles l5 and 30.

The density of the solid particles will depend on the nature of the material heated and the condition of temperature, fluidization, recycling, spraying pressures and nozzle sizes and height of column used.

The operation with the apparatus as shown in Fig. 2 is as follows.

Small particles of material to be treated,rwhich may be of different sorts are introduced or blown in through conduits l5 and 15', respectively. They are heated by heaters 16 and I6 and pass around the edges of baffles 19 and 19' and flow along the corrugated surfaces of these baiiies while solutions of materials of different sorts are introduced through spray nozzles 18 and 18' which coat the surfaces of the fluidized materials. The fluidized and coated particles are forced through outlets 80 and 80' where they are again heated and pass into the chambers 82 and 82 and over the corrugated surfaces 84 and 84 and then to the classifier tables 86 and 86'.

The particles last treated or coated in chambers 11 and ll that have been built up to the right size with alternate layers of the two sorts are segregated by tables 86 and 86' and pass through conduits or outlets and 90' to conveyor 9'2 and thence to storage or packaging equipment.

The coated particles reaching classifier tables 86 and 86 which are too small and are separated for recycling are returned through 89 and 89' to the treating chambers TI and 11, respectively, so that each particle has a coating layer of each sort applied to it alternately until it reaches a size large enough to be separated by one of the tables 86 and 86' and diverted into the conduit SI and conveyor 92.

Although this process is particularly useful for drying soap or wetting agent solutions, it may be a stage in the alcoholysis and saponification of fats where the methyl ester is saponified as it is sprayed in together with the proper amount of caustic solution in intimate contact and the released alcohol is to be recovered. The conditions required for such reactions according to the teachings of Pats. Nos. 2,383,630 and 2,383,631 are obtainable in this process, and the reactions of the solutions made to occur in the thin films which coat the fluidized carrier particles. In such a case the moisture content of the mixture can be so proportioned as to yield a virtually moisture-free soap. Glycerides may be saponified with caustic solutions by spraying them in accordance with this process, thus obtaining glycerine bearing soap solid particles in the fluidized bed of solid particles at the time and under the conditions at which the reaction takes place. Intermediate chemical solutions that are neutralized to obtain solid detergents therefrom, such as are described in Pats. Nos. Re. 20,636 and 2,159,397, can be sprayed in with caustic solutions in accordance with this invention and neutralized detergents of the desired particle size can be thereby obtained. Products such as detergents, in the form of solid particles of spherical layers can be obtained by spraying alternately solutions of solids of different solubilities; also, milk may be dried in solid particles of suitable sizes by spraying milk on a fluidized moving bed of solid particles of any suitable sort.

An important feature of the chemical processes carried out by this invention is that substantially all of the reaction between the active components in the solution or solutions treated takes place after these solutions have been deposited on the fluidized mass of solid materials and during the time the reaction requires while the mass is flowing. Under these conditions local overheating of delicate materials is avoided due to the fact that during the time chemical reactions are taking place very thin layers or very fine semi-solid particles of material are formed which are surrounded by heat conducting gases and the particles, due to turbulence, come in direct contact with heat conducting surfaces.

It will be clear from the above description that this invention comprises a feed column, an aeration zone, heat generators, spraying chambers, outlet seals for the spraying chambers, de-aeration and exhaust chambers, classifying devices and a travelling mass of aerated solid particles so arranged that all these can be combined, rearranged and multiplied in many ways to provide a suitable arrangement for the drying or chemical reaction process desired.

It wiil be seen that this invention comprises:

(a) A closed conveying system which is analogous to a liquid system wherein flows, turbulence, heat transfer, vapor pressures, interface exposuretake placegbetweeniliquids, :SOlidS and gases; and segregation and @classification .of solid particles all can be variously and accurately controlled witha minimumdeformation of the-solid particles;

' (b) A closed and confined flashing orspraying lchamber wherein the fluidized .solid particles formthe areas and surfaces surrounding these spraysyto serve. as a surfaceconveyor;

11 -mass of travelling fluidized particles: which serves-as a heat reservoir and heat transporting medium, also as a surface exposureme- :dium, and also .as a-medium wherein chemical reactions can readily take place without localized overheating;

(d) A system whereby gases are readily sep- Qarated from solid particles andthe solid particles are class-ifiged as toisize and density;

(e) An enclosed system wherein vapor pressures-are developed and controlled throughout;

= An enclosed system wherein various-forms of energy are exerted upon 1 the material in process, such-as high-frequency electric fields, ultra-violet to infra red lights, mechanicalvibrations ranging from high-frequenciesto merel riflling the material;

(g) A re-forming system. wherein particles of solids can be grown by adding successive thin layers of semi-solid materialand under conditions to gain a wide v,variety of solid particle structures.

What is claimed is:

1. Process fortreating a. solution containing solidifiable material which comprises fluidizing by means of a fluidizing gas fine solid particles of said material, transferrin said particles to a confined zone, spraying said-solution upon, said fluidized particles in said-zoneto coatthe same with 1 the solution, passing the. coated fluidized particles .upwardly out of said zone toand through an electrostatic fieldto heat the same and drivepff vaporous material from the particles, passing the heated and .coated fluidized particlesto a second confined. zone, spraying a second and different heated solution containing ,solidifiable material upon the fluidized particles in. said second zone to coat the same, passing eaidpartielesfrom the second zone upwardly through aradiant heat zone to heat thesame Iand vdrive ofl' vaporous materialfrom theparti cles,.separating the particlesfrom gaseous and vaporous material including fluidizing gas, classifying-said coated particles, withdrawing a portion of theclassificducoated particles, and returning I coated particles finer than those-withdrawn to :be

*fluidized as above described.

2. In apparatusof the character described} an aerating chamber, means forfiuidizing solid particles outside the chamber, means for introducling-i said fluidized particles totheubottom Qis 'id 210 of solid 1 particles outside said chamber, means for introducing said=mass of fluidized particles to the bottom ofsaid chamber for upwardpassage therein, a sprayer extending into said-chamber, a vertically disposed outlet for-said fluidfized particles extending into said chamber and transferring said gas-suspended mass to a confined zone to form a fluidized particles bed therein, causingv particles from said bed to flow transverselyas a shallow stream, spraying saidsolution upon said transversely flowing particlesto coat the particles with the solution, solidifying said coating, separating the particles from suspending gas, and recycling someof the particles having said solidified coating.

5. Process for producing solid particles of material from a solution containing the reagents for forming. such material, which comprises l suspending in a gas previously formed solid particles' of said material, transferring said gas-suspendedparticles to a confined zone toforina fluidized particlesbed therein, spraying said solution upon said fluidized bed in said zone to coat the particles with the. said reagents, said particles serving to: provide exposure surfaces upon which a chemical reaction in the liquid-phase takesplace, heating saidcoated, gas-suspended particlesto promote said reaction, thereafter withdrawing a portion of the coated particles, andreturning to said fluidized bed particlesflner than those withdrawn'to be coated and to provide exposure surfaces as above described.

Process for producing solid particles of soap by saponifying a i'atty acid ester with an alkali which comprises suspending ina gas, previously formed solid particles of soap, transferring said gasr suspended particles to a confined zoneto form a fluidized particles bed therein, spraying fatty .acid ester and an alkali solution upon said partioles, said particles serving to provide exposure surfaces upon which the. saponification reaction in the liquid-phase takes place, heating said coated, gas-suspended. particles to promote said reaction, thereafterwithdrawing a portion of. the ,coated particles, and returningto said fluidized -,bed particles finer than thosewithdrawn to be coated again and to provide exposure-.surfacesas abovedescribed. '7. 'Process'according to claim"6 in-which {a fatty acid glyceride is s'aponified with an. alkali. -,8. Process for. producing solidparticles of detergent material byneutralizing an intermediate detergentdorming compound which comprises suspending in a gas previously formed solid particles of said material, transferring said gas-suspended particles to a confined zone to forma fluidized. particles bed therein, spraying. said .-.intermediate compound and a solution of alkali upon said particles, said particles serving to provide exposure surfaces upon which said neutralization reaction in the liquid-phase takes place, heating said coated, gas-suspended particles to promote said reaction, thereafter withdrawing a portion of the coated particles, and returning to said fluidized bed particles finer than those with- 11 drawn to be coated again and to provide exposure surfaces as above described.

9. In a device of the character described, an aerating chamber, an inlet for fluid suspended particles at the bottom of said chamber, a heater for said inlet, a sprayer extending into said chamber, an adjustable bafile in said chamber, said bafile' having a laterally extending surface, an outlet from the chamber for said fluid suspended particles having its end in proximity to said bafiie, the baflie being positioned between said inlet and outlet and the sprayer being located above the baiiie, and a heater for said outlet.

10. Process of forming particles including solid material from solutions containing such material which comp-rises suspending in a gas previously formed fine solid particles of said material, transferring said gas-suspended particles to a confined zone, forming in said confined zone a fluidized bed of said particles having a maintained fluidized-solids surface, the point of introduction of said gas-suspended particles bein below saidfluidized solids surface, spraying said solution upon said fluidized bed of particles from a point above the surface thereof to form a coating of said solution on the particles, Withdrawing the coated, gas-suspended particles from within said bed and below the surface thereof, directing the flow of the gas-suspended particles within the fluidized bed toward the surface thereof in their flow from the point of entry to the point of Withdrawal, and passing the withdrawn particles through a heating zone to dry the said. particles, and separating the dried particles from the accompanying gas and vapors.

11. Process according to claim in which the coated, gas-suspended particles are heated by passing them through an electrostatic field.

12. Process according to claim 10 in which the coated, gas-suspended particles are heated by passing them through a radiant heat zone.

13. Process according to claim 10, wherein the dried particles are classified and the finer particles are returned to be suspended in gas and introduced into said fluidized bed in said confined zone to be further coated therein.

14. In apparatus of the character described, an aerating chamber, means for introducing fluidized solid particles through the bottom of said chamber to form and maintain a fluidized solids bed therein, means adjacent the bottom of the chamber for heating the fluidized particles introduced thereinto, bafiie means in the chamber, said baffling means having laterally extending surfaces for directing the flow of the enterin fluidized particles upwardly therein and guiding their flow, a sprayer within said chamber above said fluidized bed, means for heating a solution and for introducing the same into the chamber through said sprayer, a vertically disposed outlet for said fluidized particles extending into said chamber below the level of said fluidized particles, means for heating fluidized particles passing through said outlet, and means for separating said particles from gaseous material.

15. In apparatus of the character described, an aerating chamber, means for fluidizing solid particles outside said chamber, means for introducing said fluidized particles through the bottom of said chamber to form and maintain a. fluidized solids bed therein and to secure upward passage of the particles in said bed, a sprayer extendin downwardly into said chamber and above said bed, a vertically disposed outlet for said fluidized particles extending into said chambox below the level of said fluidized particles, and baffling means in the chamber, said bafliing means having laterally extending surfaces for directing the flow of fluidized particles upwardly from the bottom of the chamber towards the sprayer and then over the laterally extending surfaces of said baffling means towards said outlet.

16. In apparatus of the character described, an aerating and fiuidizing chamber, an inlet for solid particles at the bottom of said chamber, a heater for said inlet, a baflle extending transversely of said chamber above said inlet and terminating short of the wall of said chamber to provide a passage for said particles in fluidized state, said baflle providing. a downwardly in clined upper surface over which said particles flow after travel through said passage, a sprayer extending into said chamber above said bafi'ie, and an outlet from said chamber for said particles, said outlet having its end in proximity to the low portion of said downwardly inclined upper surface of said baifie.

' DONALD E. IWARSHALL.

REFERENCES CITED The following references are of record in the file of this patent:

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1. PROCESS FOR TREATING A SOLUTION CONTAINING SOLIDIFIABLE MATERIAL WHICH COMPRISES FLUIDIZING BY MEANS OF A FLUIDIZING GAS FINE SOLID PARTICLES OF SAID MATERIAL, TRANSFERRING SAID PARTICLES TO A CONFINED ZONE, SPRAYING SAID SOLUTION UPON SAID FLUIDIZED PARTICLES IN SAID ZONE TO COAT THE SAME WITH THE SOLUTION, PASSING THE COATED FLUIDIZED PARTICLES UPWARDLY OUT OF SAID ZONE TO AND THROUGH AN ELECTROSTATIC FIELD TO HEAT THE SAME AND DRIVEN OFF VAPOROUS MATERIAL FROM THE PARTICELS, PASSING THE HEATED AND COATED FLUIDIZED PARTICLES TO A SECOND CONFINED ZONE, SPRAYING A SECOND AND DIFFERENT HEATED SOLUTION CONTAINING SOLIFIFIABLE MATERIAL UPON THE FLUIDIZED PARTICLES IN SAID SECOND ZONE TO COAT THE SAME, PASSING SAID PARTICLES FROM THE SECOND ZONE UPWARDLY THROUGH A RADIENT HEAT ZONE TO HEAT THE SAME 